Powered and trailed vehicles are conventionally interconnected for travel by coupling hitches involving fixed locations on the vehicles. Using ball and socket type universal connections or pin type connections the required relative movement during travel is provided. The fixed locations, however, are difficult to effect particularly with large vehicle that prevent ready manual alignment for final coupling. When accurate alignment is not obtained, the towed vehicle is manually moved to proper position, requiring strength, dexterity and multiple personnel, often with an attendant risk of injury. As the tongue weight of the towed vehicle increases the skills and risks are substantially increased. The problem is particularly troublesome for large steerable wheel trailers, such as employed by the military.
Telescoping and pivoting hitches have been proposed to allow coupling between misaligned vehicles. Most are designed for lighter weight trailers and unsuited for heavy load applications. Others provide only a length dependent articulation reducing the accommodated zone of vehicle misalignment.
For instance, U.S. Pat. No. 4,515,387 to Shuck utilizes a tongue that must be fully extended before tow bar can be pivoted, thereby restricting the permissible zone of vehicle misalignment. The hitch is formed of lightweight materials not suitable for heavy trailer applications. Further, the alignment torque during retraction is borne by a sliding pin connection further reducing the ability to handle heavier trailer units. U.S. Pat. No. 5,277,447 to Blaser also provides a telescoping hitch that is pivotal only in the fully extended position.
U.S. Pat. No. 5,011,176 to Eppinette discloses a telescoping arm having a pivoting outer end allowing coupling to a misaligned vehicle. The towing vehicle must be moved forwardly to align the arm sections, at which time a slidable collar is placed around the pivot connection to prevent pivoting. Thereafter, the towing vehicle reversed to shift the arm to a retracted locked towing position. The need for forward movement, which is not always possible or convenient, and the multiple manual steps for achieving final coupling are disadvantageous.
U.S. Pat. No. 5,322,315 to Carsten discloses a fixed pivot arm having a telescoping outer end mounted on the towing vehicle. After coupling, the towing vehicle must be moved forwardly for aligning and locking the pivoting arm and thereafter rearwardly for locking the telescoping arm. U.S. Pat. No. 6,357,779 to Mok et al. also provides a fixed pivot arm having a telescoping outer end that requires forward movement for vehicle alignment and rearward movement for retraction and locking.
U.S. Pat. No. 6,328,326 to Slatten discloses a hitch tongue that is slidably and pivotally supported on a housing for coupling misaligned vehicles. The tongue and housing have complementary camming surfaces for nested alignment in a locked position. The camming surfaces provide limited aligning torque precluding usage on heavier trailer applications.